US7212642B2 - Microphone system with directional response - Google Patents
Microphone system with directional response Download PDFInfo
- Publication number
- US7212642B2 US7212642B2 US10/539,177 US53917705A US7212642B2 US 7212642 B2 US7212642 B2 US 7212642B2 US 53917705 A US53917705 A US 53917705A US 7212642 B2 US7212642 B2 US 7212642B2
- Authority
- US
- United States
- Prior art keywords
- microphone system
- hearing aid
- directivity
- sound
- fixed
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R25/00—Deaf-aid sets, i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception
- H04R25/40—Arrangements for obtaining a desired directivity characteristic
- H04R25/407—Circuits for combining signals of a plurality of transducers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
- H04R3/005—Circuits for transducers, loudspeakers or microphones for combining the signals of two or more microphones
Definitions
- the invention concerns microphone system for providing a directional response and a method for providing a directional response from a microphone system.
- the directionality is normally based on a time delay between the arrivals of the sound at two or more sound openings.
- the delay originating from the distance between microphones is matched with a delay created in the signal processor or the delay introduced by means of a mechanical delay device within the microphone for the case of dual port microphones.
- the delays are designed in accordance with free field considerations and the presence of the head is not taken into account when designing the algorithms for directionality.
- the purpose of the invention is to reduce the noise signal and to give the hearing aid user a more meaningful sense of direction of the unwanted sound according to the binaural experience associated with the use of two hearing aids.
- the hearing aid with the microphone system provides a directional response by generating a fixed forward pointing directivity pattern and a fixed backward pointing directivity pattern.
- the system adapts to the incoming sounds.
- the forward and backward directivity pattern signals are mixed at a ratio, which ensures energy minimization of the output signal under the prevailing acoustic conditions.
- the fixed directivity patterns used are optimized according to the presence of the physical shape of a human head, as described below.
- the adaptive adjustment of the mixing ratio can be controlled by a Least Means Square or Normalized Least Mean Square controller or by another algorithm serving the same purpose. Such a dynamic adjustment according to energy minimization is suggested in U.S. Pat. No. 5,473,701
- the directionality parameters are designed according to an analysis of the influence of the head on the acoustic field.
- the directionality can in general be created by a digital delay or by a more general DSP processing algorithm in the form of a FIR or IIR filter.
- a more general DSP processing algorithm in the form of a FIR or IIR filter.
- the optimization may be carried out by means of a numerical model in a computer.
- a numerical model in a computer.
- the fixed forward and backward directional algorithms are determined in such a way that the adaptive system is able to create as pronounced minima as possible when sound is coming from a number of representative directions.
- the backward and forward pointing fixed directional systems are optimized according to the best compromise over sound source directions and frequencies.
- the proposed optimal forward and backward pointing directivity patterns may in general be frequency dependent. Allowing for such a frequency dependence further increases the complexity of the solution but also creates the possibility of performing an optimization in different frequency bands individually. Hereby the system is allowed to fully compensate for the frequency dependent nature of the acoustic scattering due to the presence of the human head.
- the present invention will improve the noise suppression when the unwanted signal is on the shadow side of the head. That means that the hearing aid closest to the noise source or unwanted sound coming from side or rear will attenuate this sound as in a conventional adaptive hearing aid and that the hearing aid turning away from the source will have improved attenuation of the noise or unwanted sound.
- the hearing aid user thus gets a better idea of the position of the source, and he would for instance know better which way to turn to in order to bring the source into the looking direction in order to listen to the sound.
- FIG. 1 General layout of one embodiment of adaptive system.
- FIG. 2 Sketch of head geometry. Top view of head with sound arriving from the direction ⁇ , left ear assumed to be positioned at 90°
- FIG. 3 Calculation of directional performance at 2500 Hz. Dashed curve: Standard adaptive method; Full curve: head taken into account. Unwanted sound from 240 degrees.
- FIG. 4 Calculation of directional performance at 2500 Hz. Dashed curve: Standard adaptive method; Full curve: head taken into account. Unwanted sound from 180°
- FIG. 5 Calculation of directional performance at 2500 Hz. Dashed curve: Standard adaptive method; Full curve: head taken into account. Unwanted sound from 120°
- the difference between the present invention and previous methods is the use of a priori knowledge of the acoustic influence of the head.
- the acoustic influence of the head is predetermined from acoustic computer simulations for the geometry of a normal adult human.
- the geometry of the head used in numerical computer simulations may be more or less simplified.
- FIG. 1 General layout of an adaptive system using a Normalized Least Mean Squares algorithm is shown.
- D b
- both the ⁇ f and the ⁇ b parameter is unity which will give ordinary cardioid patterns.
- the parameters ⁇ f and the ⁇ b are determined in order to provide a directivity pattern, which when the hearing aid is placed on the head gives optimal directivity.
- the hearing aid will not provide optimum directivity in a free field with the determined parameters, but this is not relevant, because the hearing aid is supposed to function on the head.
- the directivity patterns providing the optimal performance when located in a hearing aid mounted on a head are found from computer simulations of the acoustic pressure distributions for the geometry of a normal adult human head.
- the directivity pattern representing optimum directivity when the acoustic influence of the head is taken into account is determined as follows:
- the wanted sound is taken to come from directly in front of the hearing aid user and the unwanted sound is assumed to arrive from directions in the rear hemisphere.
- the parameter to be maximized is the ratio between wanted and unwanted sound pressure. Considerations are usually restricted to the horizontal plane, however.
- the sound coming from the rear hemisphere can be assumed to always enter through the minimum in the directivity pattern. This is due to the minimization of the acoustic pressure entering the hearing aid by means of dynamic adjustment of the directional pattern through the mixing ratio of the fixed directional signals shown in FIG. 1 as ⁇ Elko .
- the optimization is obtained for a specific frequency by determining the parameters ⁇ f and ⁇ b characterizing the static directional patterns pointing forward and backward so that the adaptive system is able to create as pronounced minima as possible averaged over angles of incoming sound.
- a comparison between front to rear signal amplitudes is made for a number of directions of the incoming unwanted sound signal from the rear (for instance taking the angles from 90 to 270 degrees in 5 degree steps) while the amplitude weighting between the two fixed directional systems is adjusted according to minimum sensitivity for each direction of incoming sound, thus imitating the action of the well known adaptive procedure e.g. as proposed by Elko.
- the proposed directional filters can not compensate for the left-right asymmetry caused by the presence of a human head close to the hearing aid, but they can, however, optimize the overall directivity pattern in terms of frequency dependent measures such as DI (directivity index) or a weighted summation thereof; a typical example being an AI-DI measure.
- DI directivity index
- AI-DI measure an AI-DI measure
- FIG. 2 shows a sketch of a simplified head seen from above with sound arriving from the direction ⁇ .
- the examples shown in FIGS. 3 , 4 and 5 are analysed for left ear assumed to be positioned at 90° and using a spherical model representing the acoustic influence of the head for the frequency 2500 Hz. The results are based on the new adaptive directional approach using the same ⁇ f and ⁇ b values for all frequencies.
- the dashed curve is directional response of the system using standard adaptive method and full curve is response when the head is taken into account.
- the direction 0° is in front of user in all three cases.
- the figures show an improved attenuation except in the case of 120 degrees where the curves merge into one single curve.
- the directional performance may be unchanged compared to conventional adaptive directional systems when the source of unwanted sound is visible from the position of the ear in question.
- the directional performance is improved considerably when the head is blocking the unwanted sound from travelling directly to the ear in question. The head is influencing the sound by this screening effect and thus making it very useful to take the influence of the head into account.
- the proposed system increases the listening comfort of the hearing aid user due to an improved realism of the incoming sound levels from unwanted sound sources.
- the levels will be well attenuated in the hearing aid closest to the source of unwanted sound whereas the levels will be poorly attenuated on the shadow side of the head with respect to this sound source and this will lead to a confusing listening experience. This problem is alleviated considerably by the proposed system.
Abstract
Description
D f =|s 1 −s 2 exp(−jkdβ f)|
D b =|s 2 −s 1 exp(−jkdβ b)|
where s1 is the signal from the front microphone and s2 is the signal from the rear microphone. k is the wavenumber, d is the distance between microphones and βf determines the characteristic of the forward pointing directivity pattern and βb determines the characteristics of the backward pointing directivity pattern. In the prior art Elko algorithm both the βf and the βb parameter is unity which will give ordinary cardioid patterns. Below it is explained how the parameters βf and the βb are determined in order to provide a directivity pattern, which when the hearing aid is placed on the head gives optimal directivity. The hearing aid will not provide optimum directivity in a free field with the determined parameters, but this is not relevant, because the hearing aid is supposed to function on the head.
Claims (7)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DKPA200201988 | 2002-12-20 | ||
DKPA200201988 | 2002-12-20 | ||
PCT/DK2003/000834 WO2004057914A1 (en) | 2002-12-20 | 2003-12-18 | Microphone system with directional response |
Publications (2)
Publication Number | Publication Date |
---|---|
US20060115097A1 US20060115097A1 (en) | 2006-06-01 |
US7212642B2 true US7212642B2 (en) | 2007-05-01 |
Family
ID=32668630
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/539,177 Expired - Fee Related US7212642B2 (en) | 2002-12-20 | 2003-12-18 | Microphone system with directional response |
Country Status (7)
Country | Link |
---|---|
US (1) | US7212642B2 (en) |
EP (1) | EP1579728B1 (en) |
AT (1) | ATE373940T1 (en) |
AU (1) | AU2003287873A1 (en) |
DE (1) | DE60316474T2 (en) |
DK (1) | DK1579728T3 (en) |
WO (1) | WO2004057914A1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080170715A1 (en) * | 2007-01-11 | 2008-07-17 | Fortemedia, Inc. | Broadside small array microphone beamforming unit |
US20110228961A1 (en) * | 2010-03-17 | 2011-09-22 | Siemens Medical Instruments Pte. Ltd. | Hearing device and method for producing an omnidirectional directional characteristic |
US20110311064A1 (en) * | 2010-06-18 | 2011-12-22 | Avaya Inc. | System and method for stereophonic acoustic echo cancellation |
US9002045B2 (en) | 2011-12-30 | 2015-04-07 | Starkey Laboratories, Inc. | Hearing aids with adaptive beamformer responsive to off-axis speech |
US11089410B2 (en) | 2019-08-08 | 2021-08-10 | Sivantos Pte. Ltd. | Method for directional signal processing for a hearing aid |
Families Citing this family (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU2004310722B9 (en) * | 2003-12-01 | 2009-02-19 | Cirrus Logic International Semiconductor Limited | Method and apparatus for producing adaptive directional signals |
EP1695590B1 (en) | 2003-12-01 | 2014-02-26 | Wolfson Dynamic Hearing Pty Ltd. | Method and apparatus for producing adaptive directional signals |
EP1941782B1 (en) * | 2005-10-18 | 2018-07-18 | Widex A/S | Equipment for programming a hearing aid and a hearing aid |
US9473850B2 (en) * | 2007-07-19 | 2016-10-18 | Alon Konchitsky | Voice signals improvements in compressed wireless communications systems |
DE102008046040B4 (en) | 2008-09-05 | 2012-03-15 | Siemens Medical Instruments Pte. Ltd. | Method for operating a hearing device with directivity and associated hearing device |
EP2262285B1 (en) | 2009-06-02 | 2016-11-30 | Oticon A/S | A listening device providing enhanced localization cues, its use and a method |
EP2306457B1 (en) | 2009-08-24 | 2016-10-12 | Oticon A/S | Automatic sound recognition based on binary time frequency units |
WO2011107545A2 (en) | 2010-03-05 | 2011-09-09 | Siemens Medical Instruments Pte. Ltd. | Method for adjusting a directional hearing device |
EP2512152B1 (en) | 2011-04-13 | 2013-11-06 | Oticon A/s | Hearing device with two or more microphones |
DE102013207149A1 (en) * | 2013-04-19 | 2014-11-06 | Siemens Medical Instruments Pte. Ltd. | Controlling the effect size of a binaural directional microphone |
EP2840807A1 (en) | 2013-08-19 | 2015-02-25 | Oticon A/s | External microphone array and hearing aid using it |
CN106653044B (en) * | 2017-02-28 | 2023-08-15 | 浙江诺尔康神经电子科技股份有限公司 | Dual microphone noise reduction system and method for tracking noise source and target sound source |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4773095A (en) | 1985-10-16 | 1988-09-20 | Siemens Aktiengesellschaft | Hearing aid with locating microphones |
US5473701A (en) | 1993-11-05 | 1995-12-05 | At&T Corp. | Adaptive microphone array |
EP1017253A2 (en) | 1998-12-30 | 2000-07-05 | Siemens Corporate Research, Inc. | Blind source separation for hearing aids |
WO2000065873A1 (en) | 1999-04-28 | 2000-11-02 | Gennum Corporation | Programmable multi-mode, multi-microphone system |
WO2001095666A2 (en) | 2000-06-05 | 2001-12-13 | Nanyang Technological University | Adaptive directional noise cancelling microphone system |
WO2001097558A2 (en) | 2000-06-13 | 2001-12-20 | Gn Resound Corporation | Fixed polar-pattern-based adaptive directionality systems |
WO2002003750A2 (en) | 2000-07-05 | 2002-01-10 | Gn Resound Corporation | Improved directional microphone system |
US20020034310A1 (en) * | 2000-03-14 | 2002-03-21 | Audia Technology, Inc. | Adaptive microphone matching in multi-microphone directional system |
US7020290B1 (en) * | 1999-10-07 | 2006-03-28 | Zlatan Ribic | Method and apparatus for picking up sound |
-
2003
- 2003-12-18 AT AT03779711T patent/ATE373940T1/en not_active IP Right Cessation
- 2003-12-18 WO PCT/DK2003/000834 patent/WO2004057914A1/en active IP Right Grant
- 2003-12-18 DE DE60316474T patent/DE60316474T2/en not_active Expired - Lifetime
- 2003-12-18 DK DK03779711T patent/DK1579728T3/en active
- 2003-12-18 EP EP03779711A patent/EP1579728B1/en not_active Expired - Lifetime
- 2003-12-18 AU AU2003287873A patent/AU2003287873A1/en not_active Abandoned
- 2003-12-18 US US10/539,177 patent/US7212642B2/en not_active Expired - Fee Related
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4773095A (en) | 1985-10-16 | 1988-09-20 | Siemens Aktiengesellschaft | Hearing aid with locating microphones |
US5473701A (en) | 1993-11-05 | 1995-12-05 | At&T Corp. | Adaptive microphone array |
EP1017253A2 (en) | 1998-12-30 | 2000-07-05 | Siemens Corporate Research, Inc. | Blind source separation for hearing aids |
WO2000065873A1 (en) | 1999-04-28 | 2000-11-02 | Gennum Corporation | Programmable multi-mode, multi-microphone system |
US7020290B1 (en) * | 1999-10-07 | 2006-03-28 | Zlatan Ribic | Method and apparatus for picking up sound |
US20020034310A1 (en) * | 2000-03-14 | 2002-03-21 | Audia Technology, Inc. | Adaptive microphone matching in multi-microphone directional system |
WO2001095666A2 (en) | 2000-06-05 | 2001-12-13 | Nanyang Technological University | Adaptive directional noise cancelling microphone system |
WO2001097558A2 (en) | 2000-06-13 | 2001-12-20 | Gn Resound Corporation | Fixed polar-pattern-based adaptive directionality systems |
WO2002003750A2 (en) | 2000-07-05 | 2002-01-10 | Gn Resound Corporation | Improved directional microphone system |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080170715A1 (en) * | 2007-01-11 | 2008-07-17 | Fortemedia, Inc. | Broadside small array microphone beamforming unit |
US7848529B2 (en) * | 2007-01-11 | 2010-12-07 | Fortemedia, Inc. | Broadside small array microphone beamforming unit |
US20110228961A1 (en) * | 2010-03-17 | 2011-09-22 | Siemens Medical Instruments Pte. Ltd. | Hearing device and method for producing an omnidirectional directional characteristic |
US8477974B2 (en) | 2010-03-17 | 2013-07-02 | Siemens Medical Instruments Pte. Ltd. | Hearing device and method for producing an omnidirectional directional characteristic |
US20110311064A1 (en) * | 2010-06-18 | 2011-12-22 | Avaya Inc. | System and method for stereophonic acoustic echo cancellation |
US9094496B2 (en) * | 2010-06-18 | 2015-07-28 | Avaya Inc. | System and method for stereophonic acoustic echo cancellation |
US9002045B2 (en) | 2011-12-30 | 2015-04-07 | Starkey Laboratories, Inc. | Hearing aids with adaptive beamformer responsive to off-axis speech |
US9749754B2 (en) | 2011-12-30 | 2017-08-29 | Starkey Laboratories, Inc. | Hearing aids with adaptive beamformer responsive to off-axis speech |
US11089410B2 (en) | 2019-08-08 | 2021-08-10 | Sivantos Pte. Ltd. | Method for directional signal processing for a hearing aid |
Also Published As
Publication number | Publication date |
---|---|
AU2003287873A1 (en) | 2004-07-14 |
WO2004057914A1 (en) | 2004-07-08 |
US20060115097A1 (en) | 2006-06-01 |
ATE373940T1 (en) | 2007-10-15 |
EP1579728A1 (en) | 2005-09-28 |
DE60316474D1 (en) | 2007-10-31 |
EP1579728B1 (en) | 2007-09-19 |
DE60316474T2 (en) | 2008-06-26 |
DK1579728T3 (en) | 2008-02-11 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7212642B2 (en) | Microphone system with directional response | |
EP2088802B1 (en) | Method of estimating weighting function of audio signals in a hearing aid | |
EP3457717B1 (en) | Self-calibration of multi-microphone noise reduction system for hearing assistance devices using an auxiliary device | |
EP2877991B1 (en) | Directional sound masking | |
EP2360943B1 (en) | Beamforming in hearing aids | |
US10587962B2 (en) | Hearing aid comprising a directional microphone system | |
EP2819429B1 (en) | A headset having a microphone | |
Welker et al. | Microphone-array hearing aids with binaural output. II. A two-microphone adaptive system | |
CN104661152B (en) | Spatial filter bank for hearing system | |
AU2010346387A1 (en) | Device and method for direction dependent spatial noise reduction | |
EP3883266A1 (en) | A hearing device adapted to provide an estimate of a user's own voice | |
EP3588979B1 (en) | A method for enhancing a signal directionality in a hearing instrument | |
JP2018113681A (en) | Audition apparatus having adaptive audibility orientation for both ears and related method | |
KR101756751B1 (en) | Sound processing system with function of directionality | |
Woods et al. | Limitations of theoretical benefit from an adaptive directional system in reverberant environments | |
Ayllón et al. | Optimum microphone array for monaural and binaural in-the-canal hearing aids | |
yU-HSiang | Use of directional microphone technologies to improve user performance in noise | |
Hamacher | Algorithms for future commercial hearing aids | |
Maj et al. | A comparison of different methods for noise reduction in hearing aids | |
Boone | Optimized microphone arrays for the hearing glasses |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: OTICON A/S, DENMARK Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:RASMUSSEN, KARSTEN BO;REEL/FRAME:016526/0662 Effective date: 20050707 |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
FPAY | Fee payment |
Year of fee payment: 8 |
|
FEPP | Fee payment procedure |
Free format text: MAINTENANCE FEE REMINDER MAILED (ORIGINAL EVENT CODE: REM.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
LAPS | Lapse for failure to pay maintenance fees |
Free format text: PATENT EXPIRED FOR FAILURE TO PAY MAINTENANCE FEES (ORIGINAL EVENT CODE: EXP.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
|
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 20190501 |